Plurality clamping means



April 13, 1937. G. E. SWARTZ PLURALITY CLAMPING MEANS I Filed Jan. 211955 2 Sheets-Sheet 1 INVENTOR 5212/6.

ATTORNEY P 1937- .G. E. SWARTZ PLURALITY CLAMPING MEANS 2 Sheets-Sheet 2Filed Jan. 21, 1955 ATTORNI Patented Apr. 13, 1937 UNITED STATES FATE .1T

1 Claim.

The present invention relates to clamping a plurality of work pieceswith substantially the same clamping pressure by one clamping operation.In present day manufacture and quantity production, the prior art, inwork clamping, has not kept in step with the speed of production andconsiderable time was lost by prior means and methods of work clamping.

The present invention aims to reduce the time required for work clampingby clamping a plurality of work pieces simultaneously and by oneclamping operation.

Present day production requires that as many as possible work pieces beheld for operation thereon and that the holding of all the work piecesis attained by one clamping operation and that each of the work piecesis held with substantially the same clamping pressure as the other 5,work pieces.

Objects of the present invention are:

To provide for efllcient, simultaneous holding of a number of workpieces, each with substantially the same holding or clamping pressure asQ5 each of the other Work pieces.

To provide compensation between work holding elements so that onecompensates another for equalization of holding or clamping pressureamong all of the work holding elements.

To provide resiliency for someof the work holding elements in the samedevice.

To provide automatically shifting shoes as a feature of equalization ofthe holding or clamping pressure.

To provide a clamping plate which eventually contacts all of the workpieces but first contacts the work pieces on the resilient work holdingelements.

To provide an operating means to move the 410 clamping plate into andout of work holding or clamping positions.

To provide a releasable locking means to retain the work clamping platein a position.

Other objects will be pointed out in this specification, or will becomeobvious or apparent, or will suggest themselves upon an inspection ofthis specification and the accompanying drawings.

In the accompanying drawings, forming part of this specification:

Fig. l is a vertical section taken longitudinally through the device andshows one type of device, embodying the present invention, forsimultaneous clamping four bearing caps for drilling holes therethrough;the device is shown as having the clamping plate clamping the bearingcaps and the eccentric mechanism on dead center to retain the clamping.

Fig. 2 is an end View of Fig. 1 partly in section to better showinterior structure.

Fig. 3 is a plan View of Fig. 2 with the clamping plate removed.

7 Fig. 4 is a fragmental section taken on line 4-4 of Fig.1.

Fig. 5 is a fragmental section showing the bottom of one of the end onesof the work receiving elements.

Similar reference characters refer to similar parts throughout theviews.

For simultaneous clamping of a number of work pieces, a single clampingmember is used to clamp all of the work pieces thereon by a singleclamping movement of the clamping member. This clamping member is to bemoved upwardly Sllfficiently far to allow the difierent work pieces tobe individually placed on the work receiving end of each of the workreceiving elements and each work piece being located thereon. Springsare to normally hold the end ones of the work receiving elements up alittle higher than the middle ones. The upward movement of the end onesof the work receiving elements being limited to allow room to insert thework pieces thereon below the clamping member. When work pieces areplaced on the tops of the work receiving elements, the weights ofthework pieces are transmitted to the work receiving elements and movethe same vertically and thereby move shoes laterally and, 'the workreceiving elements being guided to move only vertically, move the shoeslaterally until all of the weights balance each other. The clampingmember, upon downward movement thereof, is to first contact the end onesof the work pieces and move the same and the work receiving elementsdownwardly and, by that movement, move the shoes laterally and some ofthem vertically also for compensating of the clamping pressure. Thevertically movable shoes to abut the ends of the middle ones of the workreceiving elements and float laterally relative thereto. This verticalmovement of some of the shoes in contact on the lower ends of workreceiving elements moves these work receiving elements upwardly untilthe work pieces thereon contact the clamping member. A continuation ofthe downward movement of the clamping member thereafter exerts clampingpressure on all of the work pieces and clamps all of them simultaneouslyagainst the clamping member. When no springs are to be used, the weightsof the work pieces shift the shoes laterally until the pressure isequalized. The clamping member, upon a downward movement thereof, firstcontacts the highest one or ones of the work pieces and moves the samedownwardly and there: by moves the shoes compensatingly laterally. Theremaining work pieces follow the same action. When all of the workpieces are moved downwardly until all of the shoes are in lateralcontact and neither one can move further laterally, all of the workpieces now being in contact on the single clamping member, the pressureof the clamping member then firmly clamps the work pieces to theclamping member and puts the entire clamping mechanism into alocked-together condition 5 to be released by an upward movement of theclamping member.

The device shown in the accompanying drawings, illustrative of thepresent invention, shows a clamping device for holding four work pieceswith 10 clamping pressure equalizing or compensating means to effectsimultaneous clamping of all of the work pieces with equal pressure.

The base A, preferably substantially inclosed to store a quantity oflubricant in the bottom 15 thereof to continually lubricate the movableelements therein and to avoid the necessity of continually payingattention to lubrication of the elements therein and relieving anoperator from the necessity of watching this lubrication and results 20in better efiiciency of the device and of the operator.

The tubular bosses H], H, I02, and I03 extend upwardly from the base Ato guide the below described work carrying elements.

The work clamping plate B is of one piece structure sufl'iciently longand wide to cover all of the work pieces which can be held in the devicein one clamping. The round pieces H and I2 project from the respectiveends of the plate B and each 30 has journaled thereon one of theeyebolts |3.

The structures which depend from each of the eyebolts are duplicates anddescription of one applies to the other also. Each of the eyebolts hasthe shank |4 externally threaded to the internal threads in one end ofthe turnbuckle IS. The stud I6 is fixed into the eccentric strap H andhas the externally threaded end |8 threaded to the internal threads inthe other end of the turnbuckle. The threads in the ends of the turn- 40buckle are right and left hand respectively. The eccentric strapembraces the eccentric H! which is fixed on the shaft 20 to rotatetherewith. The shaft 20 is journaled in the base and has the squaredends 20| for taking hold of the shaft for 45 rotation thereof.

The guide pins 2|, one for each work piece, have one end thereof fixedin the plate B and the other end projects downwardly and through and isguided in the bosses 2|| projecting sidewise 50 from the below describedwork receiving elements.

This structure maintains a specific relation between the clamping plateand the individual work receiving elements and prevents shifting of theparts.

The two posts 23 are fixed in the base and the clamping plate has twocorresponding bores therethrough, fitting to the posts, so that theplate can slide on the posts, longitudinally thereof and is guidedthereon in its movement toward and away from the base.

The work receiving element 24 has the shank 25, diametrically round foreconomy of manufacture, fitting slidably into the bore in the tubularboss l0, and has the head 26 to exchangeably 5 receive different kindsof adapters formed for different forms of work pieces. The end 28 of theguide pin 22 acts as a dowel pin to relate the different adapters to thehead.

.. The spring 29 is inserted endwise into the lower end of the shank 25and projects therefrom and extends to abutment on the wall 30 in thebase. The screw 3| is threaded into the boss l0 and has the pilot 32extending into the keyway 33 in the 75 shank 25. The keyway 33 has theend wall 34 to abut the pilot 32 and thereby limit the upward movementof the work receiving element 24 by the spring 29. The pilot may fitclosely to both sides of the keyway so that this fit can be used toprevent rotative movement of the part 24. Normally, the guide pin 22 isquite sufficient to prevent rotative movement of the part or element 24.However, the pilot 32 may be used to prevent rotative movement of theelement 24 when the guide pin is not used. The inclined face 35 isprovided on the lower end of the shank 25 for purposes appearingpresently.

The work receiving element 36 is mounted in the boss H13 and is of thesame structure as the element 24 described above.

The work receiving element 31 is mounted in the boss |0| has the shank38, also diametrically round for economy of manufacture, fittingslidably into the bore in the tubular boss I 0|, and has the head 39 andthe adapter 21 thereon similar to and for the same purpose of the upperstructure of the element 24 above described. The lower end of the shank38 is flat.

The work receiving element 40 is mounted in the boss I02 and is of thesame structure as is the element 3'! described above.

A row of main compensating shoes are slidably supported on the wall 30.Each shoe is an individual unit slidable laterally on the wall 30 and isspaced from adjacent shoes. The shoe 4| has the inclined face 42 on oneside thereof and complementary to the inclined face 35 on the shank 25.The other side of the shoe 4| has the inclined face 43 of the sameinclination as the face 42 and parallel therewith longitudinally.

The shoe 44 is of the same structure as the shoe 4! and the inclinedface 45 thereon is complementary to the inclined face 35 on the shank ofthe element 36.

The shoes 46 and 41 are duplicates of each other and of the shoes 4| and44.

A second row of intermediate shoes 48 and 49 are superimposed over therow of main shoes. Both sides of the shoe 48 have the inclined faces 50and longitudinally parallel, and complementary to the inclined faces onthe main shoes. The upper face 52 is flat. The shoe 49 is a duplicate ofthe shoe 48.

Operation The device shown and described is designed to simultaneouslyclamp four work pieces at one clamping. It is obvious that one could bedesigned to clamp more or less than the four pieces shown or to clampdifferently formed work pieces.

The work pieces 53 are bearing caps and each is to have two holesdrilled therethrough. The bushings 54, guiding the drills, are fixed inthe clamping plate and the lugs 55, upstanding from the work holdingelements, together with the lugs 56, depending from the clamping plate,cate the work pieces relative to the work holding elements and to theclamping plate and the drill guiding bushings therein.

Each work piece is first individually placed between the lugs of one ofthe adapters while the clamping plate is held in uppermost position bythe dead center condition of the eccentric mechanism, opposite thatshown in Fig. 2, which is caused by a rotative movement of the shaft.

When the four caps are placed into or onto the respective adapters, theoperator removes his hands from under the clamping plate which is thenheld against reversing or self movement downwardly by the dead centercondition of the eccentric mechanism.

A rotative movement of the shaft then. moves the clamping platedownwardly through the eccentric mechanism: and, eventually, intocontact on the upper faces of all of the bearing caps and clamps thesame into and onto the respective adapters for drilling of the holes.

While the clamping plate is in its uppermost position, the springs 29hold the work receiving elements 24 and 36 and is limited in itsuppermost positions which is determined by the pilot 3? abutting theupper wall of the keyway 33.

When the shaft is rotated for a work clamping operation, the clampingplate first contacts the end ones of the bearing caps and presses ormoves the same downwardly and also moves both of the shanks axiallydownwardly and abuts the inclined faces on the ends of the shanks on thecorresponding inclined faces on one side of the shoes M and il andthereby moves the shoes laterally on the wall 30.

This lateral movement of the shoes 4i and ti,

, relative to each other, contacts the inclined faces on the oppositeside of the shoes: 'll and 4'! onto the corresponding inclined faces onthe sides of the laterally movable shoes 48 and t9 and thereby tends tomove upwardly the intermediate shanks 38 and 52 and the bearing capssupported thereon until the latter also contact the clamping plate. Thisaction compensates and equalizes and distributes the clamping pressuresubstantially equally on all of the bearing caps. Difierent degrees offriction between contacting elements may cause this equalization to besubstantial, or not quite even, but can. be remedied by so designing thecontact faces so that the friction between the same is alike for all.This, however, is of no special import and adds to expense ofmanufacture and has not been found necessary in practice since thedesign of the inclined faces as shown provides sufiicient pressureequalization, herein called substantially, for practical purposes ofwork clamping.

When all of the bearing caps are in contact on the clamping plate, afinal rotative pull on the shaft increases. the clamping pressure andeffects clamping with a pressure equivalent to the rotative finalpressure applied to the shaft.

The eccentric mechanism is again on dead centers when the work isclamped so that the clamping plate remains locked against self releasewhen rotative pressure on the shaft is released.

The shaft is rotated in either direction for breaking the dead centercondition of the eccentric mechanism and can also be rotated in eitherdirection for bringing about work clamping and locking. When the shaftis rotated for work releasing, the dead center condition is first brokenand the clamp-ing plate is moved upwardly until a dead center conditionof the eccentric mechanism is again established and the clamping plateis held against self reversing until released by a rotative movement ofthe shaft.

In the structure shown and described, the axial pressure of the drills,due to drilling thereby, is transmitted axially to the work receivingelements which transmit the drilling pressure squarely to the wall 3%!of the casing and thereby eliminates all overhangs and spring of partsof the device and breaking of drills or spoiling of work when the drillpoints break through.

While work is being clamped by the clamping 75 plate moving downwardly,the plate first contacts the work pieces on the end ones of the row ofwork receiving elements and presses the same downwardly against theaction of the springs 29 and contacts the inclined faces on the end onesof the work receiving elements either simultaneously or one after theother. The downward movement of the end ones of the work receivingelements moves the shoes ll and ll laterally on the wall and moves theshoes it and il laterally and thereby also moves the shoes 58 and 49laterally and effects compensation among the shoes. As the clampingplate continues to move downward, the plate also contacts the workpieces on the middle ones of the work receiving elements, the lateralshifting of the shoes is continued, the middle ones of the Workreceiving elements are moved axially by the lateral movement of theshoes through the co-operating inclined faces and the clamping pressureis distributed among all of the work pieces.

It has been found that, in simultaneous clamping of a plurality of workpieces, a decided advantage is attained when the clamping pressure isapplied to one or two of the work pieces first and is then transmittedto a compensating means and to the other work pieces.

When the work pieces are fully clamped, as is seen in Fig. 1, the shoes58 and 39 have moved the middle ones of the work receiving elementsaxially compensatingly while the end ones have been moved downwardly bythe clamping plate and the shoes have effected equalization anddistribution of the clamping pressure among all of the work pieces.

The device shown and described is economical of manufacture, efficientin operation, holds a number of work pieces simultaneously, distributesthe clamping pressure substantially equally among all of the workpieces, and is self locking when either in work clamp-ing or inunclamping conditions.

It is quite obvious that the present invention can be applied toclamping means other than the one shown and described and that changesand modifications in structure and arrangement of parts thereof can bemade within the scope and spirit and intent of the present invention andof the appended claim.

Therefore, without limiting the present invention to the application andstructure as shown and described,

I claim:

A compensating means for simultaneously clamping a plurality of workpieces by one clamping movement, comprising, a plurality of individuallymovable work receiving elements guided to move only vertically, shoesmovable only laterally, shoes movable laterally and verticallysuperimposed over the first mentioned shoes, co -operating bevel fa'cesbetween the contacting ones of said shoes, said superimposed shoes beingin contact on the ends of the middle ones of said work receivingelements, the end ones of said work re ceiving elements being beveled toco-operate with the bevels on the end ones of the first mentioned shoes,a movable work clamping plate for engaging all of work pieces on saidwork receiving elements and operating the compensating means forsimultaneous clamping of all of the work pieces, a spring normallytending to move the end ones of said work receiving elements upwardly,and a stop means for limiting the up and down movement of said end onesof the work receiving elements.

GUY E. SWARTZ.

